Interface-modified NiMgO x layers with dibenzocarbazole molecules for high-efficiency perovskite light-emitting diodes

Nickel magnesium oxide is a stable hole injection layer for PeLEDs but suffers from poor hole injection and interfacial quenching. Here, we introduce [4-(7H-dibenzo[c,g]carbazol-7-yl)butyl]phosphonic acid (4PADCB) as an interlayer that passivates interfacial defects, suppresses luminescence quenching, and lowers hole injection barriers, boosting external quantum efficiency from 5.5% to 14.4%.